[ogWiFi] Looking for Directional Antenna

[Scobie, David]

Hi Ajmal, I built the dish/bi-quad/weatherproof router one afternoon
(with the assistance of copious amounts of duct tape) about three years
ago, and Ian and I removed it from my roof last night.   Except for a
bit of weathering and fading of the NEMA box, it was in great shape.

 

It was in constant service for 18 months delivering ~10Mb/s service over
a few kilometres to a modified pie plate bi-quad.  When we opened it up
it looked find, dry with no corrosion, and I realized I had built into
it a POE injector/extractor too.  I suggested to Ian that he whack it
with his favourite *nix and give it a go, I don't remember the
password.....  

 

I had incidentally, I had found at the time that although you can boost
the output of the chips up to ~251mW, that it made little difference to
the readability and strength to go over about 75mW.  The chip did
generate loads of splatter when it was cranked up, so clearly the
increased power was wasted.  I'd like to redo those tests to on several
devices and tabulate the results.   

 

Another thing I notices was it there were more unterminated live LAN
ports, that the WRT would create HUGE amounts of non specific
broadbanded noise right across the radio spectrum, with 20 and 40 metres
being particularly hard hit.

 

Shutting off the unused ports in the firmware, crimping shorting
resistors in the RJ45's and even wrapping the WRT with tinfoil tape
reduced the spurious to much lower,  but still detectable, levels.

 

David

 

 

 

From: ogwifi-bounces at list.flora.ca [mailto:ogwifi-bounces at list.flora.ca]
On Behalf Of ajmal rahman
Sent: Thursday, July 17, 2008 4:41 PM
To: Ottawa-Gatineau WiFi
Subject: Re: [ogWiFi] Looking for Directional Antenna

 

Sounds interesting...so u've made this from this dish ?

I saw one that uses a bi-quad driven element and printed circuit board
reflector.

 

I have an SWR meter but its only for hf.....dont think its any gud in
the microwave region.

 

Well, catch u later....let me know how it goes.

 

On 7/17/08, Ian Gough <igough57 at gmail.com> wrote: 

On Thu, Jul 17, 2008 at 4:00 PM, ajmal rahman <ajmal.rahman at gmail.com>
wrote:
> Ian,
>
> Gud to hear from u.....be interested in what kind o' tenna , and how
much ,
> where etc.

Well, ogWifi is just borrowing it to see if it solves a customers
problem. He wants to fire out into a park, but its through heavy
foliage. It is a converted satellite parabolic dish antenna. I am very
interested in seeing what the conversion looks like and see its
performance. I picked up a discarded dish with mount in beautiful
condition from somebody's garbage about 2 weeks ago with the thoughts
of converting it to wifi.

>
> Am also working on an outdoor helix antenna....hav all parts, just hav
to
> put it together.

I saw the plans for a helix online. It looks pretty straightforward
except for the impedance matching vane. That seemed like black magic
to me. Do you have instruments for testing it once your are done, like
a VSWR meter?
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